19981222045189I

(-5)At approximately 0700, on 22 December 1998, an American eagle ATR-42 was being taxied from the American eagle hangar ramp area at Chicago's o'Hare airport by two American eagle mechanics. As the aircraft began taxiing in an eastward direction, control was lost and the ATR-42 collided with an EMB-145 aircraft parked on a south heading, ahead and to the right of the taxiing ATR-42. The ATR-42 veered to the right, resulting in the right wing impacting the top of the EMB-145 number two reverser. As aircraft movement continued, the right wing leading edge made contact with the lower section of the EMB-145 rudder, apparently causing the ATR-42 to pivot approxiamtely 90 degrees to the right, which resulted in the ATR-42 number two propeller striking the EMB-145 number one engine cowling, cutting into the cowling and causing blade tip damage to all four blade tip of the atr. The aircraft then continued toward the left wing trailing edge of the EMB-145. Contact occurred between the left aileron of the EMB-145 and the nose section of th ATR-42, below the windshield, resulting in substantial damage to the skin of the atr and aileron of the EMB-145. Both mechanics were subjected to drug test by American eagle, and a board of inquiry (boi) was convened. After the Chicago FSDO became aware of the incident, a team of inspectors was dispatched and conducted an investigation, taking photographs and surveying the vicinity of the collision. Photographs at the scene revealed a distinct set of rubber scrub marks which appeared to be from the nose tires of the ATR-42 as it pivoted subsequent to contact with the EMB-145. The company boi was interrupted so that inspectors could interview the mechanics. Full written and verbal statements were provided by the mechanics involved. Both aircraft are currently undergoing repair at Chicago. In statements and interviews, both mechanics stated that hydraulic failure occurred, resulting in loss of nosewheel steering and braking effectiveness. A review of the aircraft logbook by FAA inspectors revealed no outstanding or previous descrepancies suggesting a problem with the hydraulic system or brake systems. At the request of FAA inspectors and the American eagle engineering department, the hydraulic system underwent an operational check in accordance with the atr maintenance manual, 29-31-00. This check revealed that both the blue and green hydraulic systems operationally checked good as indicated on American eagle non-routine work card no. 926109 a copy of which is attached to this report. Findings were that the mechanic taxiing the aircraft had been on duty for approximately 22 hours at the time of the incident. There was no ice or snow in the ramp taxi area that would have adversely affected braking effectiveness. Other American eagle mechanics interviewed stated that they sometimes work overtime in excess of their normal 10 hour shifts. American eagle airlines issued internal communications from the managing director of line maintenance covering daily safety briefings and employee duty time limitations. Included in this memo was the requirement for all supervisors and acting supervisors to conduct a daily safety briefing prior to the start of each shift, discussing pertinent safety issues, and to emphasize a 20 hour on duty time limitation for mechanics at base meintenance stations.